The Defence Force concedes there have been some "teething issues" with its $1.3 billion health contract, but has sought to reassure personnel that the changes are not about cost cutting.
Last month, ABC News Online revealed the company contracted to provide health services to about 80,000 defence personnel, Medibank Health Solutions (MHS), was .
Medical groups said part of the reason was because MHS had cut specialists' fees to below the rates recommended by the Australian Medical Association (AMA).
In an internal memo obtained by ABC News Online, the head of the ADF's Joint Health Command, Rear Admiral Robyn Walker, said that despite media reports, thousands of specialists had signed up to the new arrangements.
"We are continuing to work very hard with Medibank to expand the provider list and there is specific activity underway to address providers in Darwin, Townsville, Canberra and the Shoalhaven," she wrote.
Rear Admiral Walker said 80 per cent of Australian Defence Force (ADF) personnel requiring specialist treatment or surgery had been referred to someone on Medibank's preferred provider list.
The remaining 20 per cent have been sent to other health professionals.
The AMA has previously expressed concerns that some ADF personnel had been given generic referrals to specialists because not enough health professionals had signed up, resulting in some patients being sent to the wrong doctor.
Rear Admiral Walker says there have been some issues with the new central appointments process, but it is constantly being "refined".
"(Joint Health Command) is... aware of six cases where errors occurred in making appointments for members with the wrong provider. These were corrected without clinical impact.
"To my knowledge no ADF member has not received the specialist medical appointment or acute treatment they require.
"The contract (with Medibank Health Solutions) will improve efficiency and effectiveness of defence health services and standardise the delivery of health care to ADF personnel.
"This is about value for money, not cost cutting."
In the memo Rear Admiral Walker says the ADF had no control on fees under the previous arrangements, meaning some doctors were charging up to 140 per cent above AMA rates.
In relation to on-base medical officers, Rear Admiral Walker says there have been some "deficiencies" in permanently filling some positions, particularly at HMAS Stirling in Perth, HMAS Cairns and the Robertson Barracks in Darwin.